Free Radical Chlorinations in Halogenated Solvents:  Are There <i>Any</i> Solvents Which Are Truly Noncomplexing?

Abstract

The free radical chlorination of alkanes was examined in several solvents. The results of these experiments suggest that Cl• forms complexes with halogenated solvents and that these complexes exhibit higher selectivity in hydrogen abstractions than “free” chlorine atom. The observed selectivity decreases with increasing Cl-content of the solvent (paralleling the increase in the ionization potential of the solvent), and selectivity is greater in bromoalkane solvents compared to chloroalkanes, suggesting that these are donor/acceptor-type complexes.